Treatment of hydrocarbons



Patented Mar. 23, 1943 2,314,388 TREATMENT OF HYDROCARBONS Joseph A. Chenicek, Chicago, Ill., assignor to Universal Oil Products Company, Chicago, III., a

corporation of Delaware No Drawing. Original application December 28,

1939, Serial No. 311,316. Divided and this application July 26, 1940, Serial No. 347,765

18 Claims.

This invention, which is a division of my copending application Serial 311,316 which was filed December 28, 1939, relates to a method for suppressing deterioration of olefin-containing hydrocarbon distillates such as results from the catalytic eiiect of metal compounds on oxidation reactions involving unsaturated hydrocarbons and resulting in the formation of gum.

The use of gasoline gum inhibitors to prevent or minimize oxidation reactions resulting in the formation of objectionable peroxides, gums and other deleterious oxidation products has been practiced. They are particularly useful in cracked, reformed and polymer gasolines which contain relatively high concentrations of monoolefins and somewhat smaller concentrations of other unsaturated hydrocarbons such as diolefins.

The function of inhibitors is primarily to minimize or prevent such oxidation reactions and thus keep the motor fuel in satisfactory condition for use in internal combustion engines. They tend to prevent losses in anti-knock value which accompanies oxidation of this type of gasoline. Among the materials which have been used are various phenolic, amino, and aminophenolic compounds as well as fractions of wood like which are oxidation catalysts.

tar oil, etc., which are usually added to the gasoline in concentrations of approximately 0.001-0.1%, depending upon the eiiectiveness of the particular compound used and the gasoline to which it is added.

Although inhibitors are used in both treated and untreated gasolines, it is with the latter type that they find the greatest application. Treated gasolines may be defined as those which have been subjected to chemical refining processes such as sulfuric acid, fuller's earth, and the like, either with or without a subsequent sweetening treatment. Untreated gasolines may be said to be those which have received no refinement beyond possibly caustic washing and/or sweetening. The former type of gasoline is usually relatively stable and requires little or no added inhibitor, although the use of inhibitors has been practiced to supplement other refining methods. In the case of untreated gasolines, on the other hand, many of them are unstable and require the protection aiiorded by inhibitors to prevent undue deterioration during the time they are in storage.

Practically all gasolines require some form of .sweetening treatment in order to-improve the odor thereof and produce a product having a negative doctor test. The sodium plumbite or doctor process, as well as the hypochlorite sweetening process have been used in the past with considerable success. During recent years, the so-called copper sweetening process has been developed in which gasoline is contacted with a copper-containing reagent. As a result of the presence of relatively minor amounts of impurities in such gasolines, the sweetened gasoline usually contains relatively small amounts of copper compounds which have a catalytic effect on oxidation reactions which may result when the gasoline comes in contact with air. Various methods have been developed for removing such copper compounds including treatment with alkalior alkaline earth-metal sulfides, and heavy metal sulfides such as zinc sulfide and the like. In some instances, however, these reagentsmay not be completely efi'ective in removing the copper from the gasoline and as a consequence the gasoline may have a reduced stability and susceptibility to added gasoline gum inhibitors. Moreover gasolines come in contact with various metals in the course of refining, storing and shipping operations, and this may result in the gasoline containing minute amounts of such metals as copper, iron, cobalt, nickel and the It is witha method of preventing depreciation due to the presence of such catalysts that this invention is concerned.

In one specific embodiment the present invention comprises a method for suppressing the catalytic action of heavy metal compounds which may be contained in hydrocarbon distillatessuch as cracked gasoline and which tend to promote the formation of gum therein by adding to said gasoline approximately 0.0001-0.01% of a condensation product of a poly-hydroxybenzaldehyde with an aminophenol either with or without a gasoline gum inhibitor.

Compounds of this type may be represented by the general formula:

wherein R may be a substituent group such as an alkyl group or may be a hydrogen atom and X may be an alkyl group or a hydrogen atom. A representative compound of this type is 2-4 dihydroxybenzal-ortho-amlnophenol. Another compound is 2-4 dihydroxybenzal-para-aminophenol.

These compounds may be made by dissolving the components in alcohol, mixing the alcoholic solutions, and warming the mixture. The

In some cases the compounds may be used in the gasoline without. added gum inhibitors. This is particularly true when used in connection with straight-run distillates or cracked gasolines which have been refined to an adequate degree of stability such as by acid-treatment or other suitable methods. However these compounds are not of themselves gasoline gum inhibitors except to a minor extent, so that they do not result in a gasoline of improved stability except when metal compounds are present therein.

However, the usual method of application is to add both the suppresser and the gasoline gum inhibitor simultaneously. The resulting induction period is usually the same or slightly increased over that obtainable with the inhibitor alone in a gasoline free of metal compounds. The suppresser may be dissolved in the gasoline gum inhibitor. As a rule, smaller amounts of the suppresser are required than of the gum inhibitor so that a relatively minor amount of the suppresser may be added to the inhibitor, say for example, less than 50% of the total mix ture. When using inhibitors of the aminophenol type, the hydroxy-benzaldehyde in alcoholic solution can be added directly to the inhibitor.

The following examples are given to illustrate the usefulness of the invention, but should not be construed as limiting it to the compounds shown therein.

Example 1 A Mid-Continent gasoline containing 0.75 mg. of copper per liter had an induction period upon the addition of a commercial gum inhibitor of 1'75 minutes. Upon the addition of 0.005% of 2-4 dihydroxybenzal-ortho-aminophenol the induction period was increased to 300 minutes.

Example 2 A Pennsylvania cracked gasoline after copper sweetening was found to contain 1 mg. of copper per liter of gasoline. The induction period when the copper was completely removed was approximately 100 minutes and with the copper present was approximately 40 'minutes. By adding 0.004% of 2-4 dihydroxybenzal-para-aminophenol the induction period was increased to approximately 90 minutes and upon the addition of a commercial gum inhibitor was increased to 370 minutes. When the commercial gum inhibitor (0.01%) was used without the suppresser the induction periodwas 150 minutes.

I claim as my invention:

1. A method for suppressing the catalytic action of metal compounds on gum formation in hydrocarbon distillate which comprises adding to the distillate a jpolyhydroxyfbenzal-aminophenol.

2. A method of suppressing the catalytic effect of metal compounds on gum formation in hydrocarbon distillate which comprises adding to said distillate a relatively minor portion of a dihydroxybenzal-aminophenol.

2,s14,saa

3. A method of suppressing the catalytic eflect of metal compounds on gum formation in olefincontaining hydrocarbon distillate which oomprises adding to said distillate a relatively minor portion of a dihydroxybenzal-aminophenol.

4. A method of suppressing the catalytic eflect of metal compounds on gum formation in olefincontaining hydrocarbon distillate which comprises adding to said distillate a relatively minor portion of a 2-4 dihydroxybenzal-aminophenol.

5. A method of suppressing the catalytic effect of metal compounds on gum formation in olefincontaining hydrocarbon distillate which comprises adding to said distillate a relatively minor portion of a 2-4 dihydroxybenzal-ortho-aminophenol.

6. A method of suppressing the catalytic effect of metal compounds on gum formation in olefincontaining hydrocarbon distillate which comprises adding to said distillate a relatively minor portion of a 2-4 dihydroxybenzal-para-aminophenol.

7. Motor fuel comprising olefinic gasoline containing a gasoline gum inhibitor and a dillydroxybenzal-aminophenol.

8. A hydrocarbon product comprising olefincontaining distillate containing a dihydroxybenzal-aminophenol.

9. A method for suppressing the catalytic effect of metal compounds on deterioration of hydrocarbon distillate in the presence of oxygencontaining gas which comprises adding to the distillate a compound having the following general formula:

10. A method for suppressing the catalytic eifect of metal compounds on deterioration of hydrocarbon distillate in the presence of oxygencontaining gas which comprises adding to the distillate a compound having the following effect of metal compounds on deterioration of hydrocarbon distillate in the presence of oxygencontaining gas which comprises adding to the distillate a compound having the following general formula:

wherein R is an alkyl group.

12. A method of retarding gum formation in a hydrocarbon distillate containing constituents normally subject to gum formation by oxidation on exposure to an oxygen-containing gas and also containing a metal compound tending to act as an oxidation catalyst on said gum formation, which method comprises adding to said distillate a suppressor compound comprising essentially a po yhydroxybenzal-aminophenol 2,314,388 tending to materially suppress said catalytic action of said metal compound, and also adding to said distillate a gum inhibitor normally effective to materially retard gum formation in said distillate upon said suppression of said catalytic action of said metal compound.

13. A method as defined in claim 12 and further characterized by forming a mixture of said suppressor compound and said gum inhibitor and adding the mixture to said distillate.

H14. A hydrocarbon product comprising olefinic distillatecontaining, as a suppresser for the catalytic efiect of metal compounds on gum formation, a relatively small amount of a polyhydroxvbenzal-aminophenol.

15. Motor fuel comprising olefinic gasoline containing a relatively small amount of a polyhydroxybenzal-aminophenol.

16. Motor fuel comprising olefinic gasoline containing a relatively small amount of a polyhydroxybenzal-aminophenol and a gum inhibitor.

17. A hydrocarbon product comprising olefinic distillate containing, as a suppresser for the catalytic efiect of metal compounds on gum formation, a relatively small amount of a 2-4- dihydroxybenzal-aminophenol.

18. Motor fuel comprising olefinic gasoline containing a relatively smallamount of a 2-4- dihydroxybenzal-aminophenol. V

x JOSEPH A. CHENICEK. 

